This invention relates to an apparatus and method for the inspection of cigarettes. More particularly, this invention relates to inspection of cigarettes using a rolling drum and a rolling block to expose nearly 360.degree. of a cigarette for a machine vision system to view cigarettes at two positions.
It is well known to test cigarettes or other rod shaped smoking articles prior to introduction into boxes or packets for sale to consumers. The testing is for quality control and is intended to uncover unsatisfactory conditions in the cigarettes, such as stem holes, skewed or torn tipping, tobacco under the rod seam, torn ends on the cigarette, and spots from glue, flavors or oil. It is the goal of cigarette manufacturers to eliminate these unsatisfactory conditions.
Quality control in cigarette production must continually advance as the speed of cigarette production increases. Inspection systems must also advance to accommodate the faster speeds of production. Therefore, while prior systems are known, these systems do not always perform completely satisfactorily at the higher speeds of current cigarette production. Further, the known testing methods may not test for some unsatisfactory conditions. Current inspection devices rely on pressure drops to find unsatisfactory conditions such as loose ends, missing filters and stem holes. However, they do not test for all the unsatisfactory conditions listed above.
Tobacco smoking articles, such as cigarettes and cigars, are made into rods on machines which take cut filler that is formed into a continuous rod of tobacco, and encircles the tobacco with a continuous ribbon of paper which is glued and heat-sealed. The continuous tobacco rod is formed and sealed in the making machine and then proceeds to another processing machine, such as a tipper. The tipper attaches a filter plug cut to the appropriate length between two tobacco rods. The tipper applies glue and wraps tipping paper around the filter segment and a portion of the tobacco rods. This creates a double cigarette length. The two cigarettes are then cut and oriented into a single row. A tipper as described is shown, for example, in U.S. Pat. No. 3,527,234 to Hinzmann. It is the completed cigarette that is inspected for unsatisfactory conditions.
Optical scanning of cigarettes during production is taught by U.S. Pat. No. 4,277,678 to Wahle et al. There, a cigarette is inspected in the tipping machine by two optoelectrical units mounted on a single rolling drum. The cigarette is stopped in its path and rotated using a separate rotary element while the optoelectrical units scan the cigarette's wrapper for unsatisfactory conditions. Each optoelectrical unit scans the entire cigarette for particular unsatisfactory conditions.
Other cigarette inspection systems test the cigarettes at several testing stations. Each station tests the cigarette for one or two different types of unsatisfactory conditions. U.S. Pat. Nos. 4,403,620 to Joseph et al., 4,484,591 to Wahle et al. and 4,901,860 to Wahle et al. all teach separate testing stations for different unsatisfactory conditions in cigarettes.
Still other cigarette inspection systems use more than one drum to create more than one inspection zone. U.S. Pat. No. 4,639,592 to Heitman passes cigarettes before optical inspection devices located at certain points along a predetermined path. The path requires at least two vacuum drums each to expose one side of the cigarette. Note that Heitman specifically prefers to not mechanically rotate the cigarette. Great British Patent No. 2,221,029 teaches a similar method.
Further, other devices inspect cigarettes before they are completed. For example, U.S. Pat. No. 4,350,170 to Baier teaches inspection of the cigarette rod as it comes off the rod making machine by passing the rod through an annular housing. A similar device is taught by U.S. Pat. No. 4,208,578 to McLoughlin et al.
None of the devices known currently in the field, inspect cigarettes in the simple, effective, compact system as disclosed herein. This invention provides a method and apparatus to inspect cigarettes at the speeds of modern production while inspecting nearly the entire cigarette.